High-resolution spectroscopy of the [18.4]2.5 – X2Δ5/2 transition of ruthenium monoboride (RuB)
Laser-induced fluorescence spectra of the (0, 0), (1, 0) and (0, 1) bands of the [18.4]2.5 – X2Δ5/2 transition have been recorded at high-resolution for several isotopologues of ruthenium monoboride (RuB). We report band origins and rotational parameters for 12 of the 14 possible isotopologues (7 for each of Ru11B and Ru10B) as well as hyperfine parameters of 99RuB and 101RuB. An anomalous isotope shift in the (0, 0) and (0, 1) bands indicates a weak perturbation in the [18.4]2.5 v = 0 vibrational level. The observed hyperfine structure is mainly due to the nuclear spin (I = 5/2) of the two Ru isotopes. Hyperfine structure due to the 11B and 10B isotopes was not resolved and resulted in, at most, a slight broadening of the lines. The magnetic hyperfine parameters help to confirm the (11σ)2(5π)4(2δ)3 configuration of the ground electronic state and provide insight into the configuration of the excited states.